summaryrefslogtreecommitdiff
path: root/lib/comp/zstd.c
blob: bc94b2db69629c0097a5b93514c6e34c781db3dc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
/* SPDX-License-Identifier: GPL-3.0-or-later */
#include "config.h"

#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <ctype.h>

#include <zstd.h>

#include "internal.h"

#define ZSTD_DEFAULT_COMPRESSION_LEVEL 15

typedef struct {
	compressor_t base;
	ZSTD_CCtx *zctx;
	int level;
} zstd_compressor_t;

typedef struct {
	uint32_t level;
} zstd_options_t;

static int zstd_write_options(compressor_t *base, int fd)
{
	zstd_compressor_t *zstd = (zstd_compressor_t *)base;
	zstd_options_t opt;
	(void)fd;

	if (zstd->level == ZSTD_DEFAULT_COMPRESSION_LEVEL)
		return 0;

	opt.level = htole32(zstd->level);
	return generic_write_options(fd, &opt, sizeof(opt));
}

static int zstd_read_options(compressor_t *base, int fd)
{
	zstd_options_t opt;
	(void)base;

	if (generic_read_options(fd, &opt, sizeof(opt)))
		return -1;

	opt.level = le32toh(opt.level);
	return 0;
}

static ssize_t zstd_comp_block(compressor_t *base, const uint8_t *in,
			       size_t size, uint8_t *out, size_t outsize)
{
	zstd_compressor_t *zstd = (zstd_compressor_t *)base;
	size_t ret;

	ret = ZSTD_compressCCtx(zstd->zctx, out, outsize, in, size,
				zstd->level);

	if (ZSTD_isError(ret)) {
		fputs("internal error in ZSTD compressor\n", stderr);
		return -1;
	}

	return ret < size ? ret : 0;
}

static ssize_t zstd_uncomp_block(compressor_t *base, const uint8_t *in,
				 size_t size, uint8_t *out, size_t outsize)
{
	size_t ret;
	(void)base;

	ret = ZSTD_decompress(out, outsize, in, size);

	if (ZSTD_isError(ret)) {
		fputs("error uncompressing ZSTD compressed data", stderr);
		return -1;
	}

	return ret;
}

static void zstd_destroy(compressor_t *base)
{
	zstd_compressor_t *zstd = (zstd_compressor_t *)base;

	ZSTD_freeCCtx(zstd->zctx);
	free(zstd);
}

compressor_t *create_zstd_compressor(bool compress, size_t block_size,
				     char *options)
{
	zstd_compressor_t *zstd = calloc(1, sizeof(*zstd));
	compressor_t *base = (compressor_t *)zstd;
	size_t i;
	(void)block_size;

	if (zstd == NULL) {
		perror("creating zstd compressor");
		return NULL;
	}

	zstd->level = ZSTD_DEFAULT_COMPRESSION_LEVEL;

	if (options != NULL) {
		if (strncmp(options, "level=", 6) == 0) {
			options += 6;

			for (i = 0; isdigit(options[i]); ++i)
				;

			if (i == 0 || options[i] != '\0' || i > 6)
				goto fail_level;

			zstd->level = atoi(options);

			if (zstd->level < 1 || zstd->level > ZSTD_maxCLevel())
				goto fail_level;
		} else {
			goto fail_opt;
		}
	}

	zstd->zctx = ZSTD_createCCtx();
	if (zstd->zctx == NULL) {
		fputs("error creating zstd compression context\n", stderr);
		free(zstd);
		return NULL;
	}

	base->destroy = zstd_destroy;
	base->do_block = compress ? zstd_comp_block : zstd_uncomp_block;
	base->write_options = zstd_write_options;
	base->read_options = zstd_read_options;
	return base;
fail_level:
	fprintf(stderr, "zstd compression level must be a number in the range "
		"1...%d\n", ZSTD_maxCLevel());
	free(zstd);
	return NULL;
fail_opt:
	fputs("Unsupported extra options for zstd compressor\n", stderr);
	free(zstd);
	return NULL;
}

void compressor_zstd_print_help(void)
{
	printf("Available options for zstd compressor:\n"
	       "\n"
	       "    level=<value>    Set compression level. Defaults to %d.\n"
	       "                     Maximum is %d.\n"
	       "\n",
	       ZSTD_DEFAULT_COMPRESSION_LEVEL, ZSTD_maxCLevel());
}